Electron discharge device



Jan. 4, 1949. A. G. THOMAS ELECTRON DISCHARGE DEVICE Filed Feb. 16, 1945FIGZ FIG. I

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Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE 2,457,948 ELECTRONDISCHARGE DEVICE Albert G. Thomas, Lynchburg, Va.

Application February 16', 1945, Serial No. 578,244 g Another object isto provide an electronic relay in which a principal pool cathode typerelay is combined with the controlling electronic tube.

A further object is the provision of an electronic relay for largecurrents combined with a control electronic tube or relay for relativelysmall currents, in one envelope.

An additional object is to provide an electronic relay for largecurrents combined with an electronic control relay for smaller currentsso that the smaller relay is efiectively cut out of circuitautomatically when the larger relay conducts appreciable current.

Another object is the provision of an electronic relay combined with acontrol tube which automatically determines thefiring point of thevoltage cycle.

Other objects will appear in the following description:

In the drawings:

Figure 1 is a part sectional elevation of an electronic relay with pooltype cathode combined in the same envelope with a gaseous or otherelectronic control relay or tube.

Figure 2 is a part sectional elevation of a device similar to that shownin Figure 1 but with in-built means for effectively removing the controlrelay from the circuit when the pool cathode relay conducts suflicientcurrent.

Figure 3 is a part sectional elevation of a combination pool cathoderelay and hot filament relay, the filament being in series with theline.

Figure 4 is a part sectional elevation of an electronic relay or tubeshown connected in a circuit. The filament of this tube is connected inseries with the anode voltage source.

In Figure 1, envelope I' of glass or othersuitable material has sealedcross partition 2 of similar material forming chambers A and B Chamber Ahas anode 3 of any well known construction such as of nickel, andfilament cathode 4 and grid 3 are provided. Suitable leads from theanode and grid are sealed in envelope I in known manner and the leads8--9- to cathode 4 are: preferably sealed in partition land are broughtout of the envelope as shown sothat;

9 Claims. (Cl. 250-275) rent source H) which may 6 to cathodel which mayelement 4a adapted to to battery or other curbe the secondary of theymay be connected a transformer.

Rod 6' which may be of graphite or other suitable material, is supportedby connected lead II, or in any other manner. Lead ll connects rod haveconnected heater emit electrons freely. Element 4a is preferably coatedwith barium oxide or other suitable material of relatively low workfunction. If desired, hot wire cathode 4 h alone may be used.

Rod 6 clips into cathode pool l2 of mercury or suitable material andpreferably nickel or graphite anode I 3 is fastened in chamber B to leadl4 sealed in envelope l. Other means of support such as glass stemscould be used.

Electrically conducting plate I of suitable material such as metals orthe like, is placed in contactwith pool l2 and is connected with lead l5sealed in envelope I. The device is preferably positioned vertically asindicated.

Anodes 3- and I3 are connected to line conductor IB- and lead [5 fromcathode l2 for chamber'B is connected to line I! through load L whichmay be a motor or any other current operated device.

Grid 5 is connected with terminal l8 and terminal' [9- is connected withcathode 4--4a.

Rod 6 may be composed of graphite or of material which changes itsresistance markedly withvariation of current passing through thematerial. Various compounds or mixtures of silicon carbide, carbon, zincoxide, boron or the like, have such characteristics. If rod 6 is made ofa suitable material of this type it will normally oifer a relativelyhigh resistance which can be greatly reduced to facilitate forming anare when current is passed through the rod tomercury or other material I2.

Rod 6 may also consist of graphite mixed with carborund-um crystals,silica, or other finely divided or cystalline particles in order tofacilitate the forming of spots of highpotential gradient. If desired,therod may comprise a metal rod coated'with graphite or other materialfor better conductivity through the graphite. A smaller unit can be madein this way. Semi conducting material'such as selenium, copper oxide,aluminum oxide or the equivalent may also be effective as means forproducing a high potential gradient between the rod and the cathodematerial l2.

ber B from anode cury pool l2, for instance, will then become thatrelatively heavy current passes ionized so from line 16 through anode l3and chamber B to cathode I2 and so through load L. 3

If pulsating direct current is applied in lines it and H or alternatingcurrent, then grid 6-pool l2 junction may be made negative to stop thecurrent flowin chamber B when the potential difference between lines l6and l! falls below a critical value.

Chamber A preferably contains gas such as argon, or argon and mercury inorder to' provide sufficient current flow. This chamber may be placed tothe side of chamber B, within that chamber, or below it as desired.

This combined heavy duty electronic valve and relatively small currentcontrol valve is much more convenient to use than prior devices whichhaveto be assembled in various groups. 7

Envelope I may be of metal which may have cooling fins if desired.Conductors l5 and 16 would be suitably insulated from the metalenvelope.

In Figure 2 the construction is the same as in Figure 1, as indicated bylike numerals, except that in this modification grid 5 is connected tocathode 4-4a. through resistor or impedance element when the gridcircuit is closed by connecting a source of potential between terminalsl8-l9. This source can be a battery, generator, a current-carryingresistor, or a condenser or inductance which could also be wound to haveconsiderable reactance. Anode I3 is connected-to the grid-connected endof resistor 20 the other end of which is connected to line 16 as well asto cathode 4-4a.

By means of the above described arrangement chamber A conducts currentto rod 6 until current conduction between anode l3 and cathode i2 occursat which time the current passing through resistor 20 from line l6causes a poten: tial drop in resistor2fl which biases grid 5 negativelywith respect to cathode 44a' so that cur rent conduction from anode 3 tothat cathode is stopped or reduced when current is passed from anode l3to cathode l2. In this way the-starting.

relay is automatically cut out of circuit or increased in efiectiveresistance when the power or larger relay passes current.

In case sufficient gas is contained in chamber A, then alternatingcurrent orpulsating direct current potential should be applied betweenposi tive line 16 and negative line H. Resistor 20 can be of suficientlyhigh value so that it will cut off current fiow in chamber A at arelatively low value of current in chamber B. The resistor is preferablysealed in the envelope l but may be placed outside if desired, or in anyother.

suitable location.

This form of the invention may be changed. from a non-conducting toconducting state by increasing the voltage betweenlines l6 and 11 ifterminals I8 and I9 are connected or by connecting these terminalstogether directly or through a potential source which biases grid 5'positively with respect to cathode 4-4a, if necconductor2l is samenumerals as before.

4 essary. The negative potential drop across resistor 20 can then besufficient to overcome the positive bias.

An advantage of this modification is that the starting relay is cut onand off by one operation instead of by two as before, if the relay inchamber A is normally non-conducting. By varying the bias of grid ,5 orthe value of resistor 20'the pointinthe line cycle at which cut off inchamber B occurs can be regulated.

" In Figure 3, like parts are designated by the In this form of theinvention line 16 is connected to anode .3, as be fore,.but cathodefilament 4 is connected in series with lines It and I! by means ofconductors 25,

22, and .23 wholly or partially sealed in envelope 1., Conductor 22 isconnected to line ll on the line side of load L the other terminal ofwhich is connected to cathode plate or other element l.

Resistor 23a is preferably connected in series with conductors 2|, 22,cathode 4, and conductor 22. .If this resistor is used then lead 24 frombrought out as shown and connects with tenninal25 which may be connectedto the positive: terminal of biasingbattery'Zfi the negativeterminal ofwhich maybe connected to ter minal .2'L' Conductor I4 is connected withcon- I ductor 23 or filament 41as indicated. A switch 29 can be providedfor opening and closing the filament circuit. 1 I

In operation, if switch 29 is closed and line it is connected to.anode-3 and line H is. connected I to the junction of conductor 22 andconductor 28 irom load-L, thencurrent will pass through resistor 23a andfilament 4 to heat that cathode.

Nil appreciable current will pass through chamber B and-load L howeverif grid 51s biased sufiicient- H ly negatively withrespect to cathode4-4a. Grid I 5 may be'biased'by a' L that-mercuryvapor in chamber B willbecome cathode l2, load L and conductor 28.

I potential source suitably connected between terminals [8 and 69. Ifthen, grid 5. is fmade positive or sufficiently less negative,'currentwill pass from anode 3 to cathode 4- 4aand through rod 5 to produceelectrons so ionized landcurrent conduction from line it to line 11will'take place through conductor 2i, resistor 23a, conductor 14, anodel3, chamberB,

' If fluctuating or alternating potential occurs between linesl6 and llthen current flow through chamber B and load L can be stopped by makinggrid 5 sufficiently negative with respect to cathode 4-40 so that thestarting current in chamber A r willbe prevented bya relatively lowanode potentialpoint. Another terminal 18 to terminal 2'1 as indicated.Then grid 5 is normally negatively biased by battery orotherpotentialsource 26,50 that there is no appreciable current conduction inchambers A and B. when the potential betweenlines l6 and I1 is below apredetermined valuea At some point in the cycle, however, this potentialwill rise to the critical value so that sufiicient current flows throughresistor 23a to. bias grid 5 positively or sufiicientlyless negativelywith respect to cathode 4--4a to allow current conduction in chamber Afrom anode 3 to cathode 4-41: with the result that current conduction inchamber B and through load Loccurs. The point in the line potetialcycle'at which current conduction through chamber B and loadL occurs canthen be regulated by varying the potential of source 26 or by varyingthe value of resistance 23a which may be tapped or placedoutsideenvelope I. In this way mode of operation is to connect grid.

the average magnitude of current through load L can be varied.

This modification is very useful and convenient since it can beconnected directly in the line, only a few connections being necessary.This device is therefore much simpler to use than prior gaseous relayswhich require numerous connections and circuits. It will be observedthat no current passes through the load until chamber B conducts, but ifthe current through filament 4 is not objectionable, conductor 22 can beconnected on the opposite side of load L.

The bias of grid 5 can be adjusted to compensate for the potential dropacross resistor 23a, due to normal filament drain. The current throughthis resistor is increased when chamber B is fired.

Resistor 22a is placed in series with conductor 22 to insure a potentialdifierence between anode I3 and cathode l2.

A circuit showing a relay tube similar to the upper relay of Figure 3 isillustrated in Figure 4. The filament 4 can be supplied with currentfrom anode potential source 39 through both the load L and line 32 ifswitch 3| is closed and through load L if the switch is open. Theresistance of cathode filament 4 or its connected lead may be sufiicientto keep the initial current flow through the load to relatively lowvalues, if load L requires considerable current in proportion to thatsupplied to the filament. Load L will then receive its full current whengrid 5 is of proper polarity and potential.

Various other modifications can be readily made without departing fromthe general principles I have disclosed.

What I claim is:

1. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connecting said first anode and oneterminal of said first cathode, and another impedance element connectingthe other terminal of said first cathode and said pool type cathode.

2. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connecting said first anode and oneterminal of said first cathode, another impedance element connecting theother terminal of said first cathode and said pool type cathode, saidgrid being electrically connected with said first anode.

3. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber, a pool typecathode, a. second anode, and a control element in the other saidchamber; an impedance element connecting said first anode and oneterminal of said first cathode, another impedance element connecting theother terminal of said first cathode and said pool type cathode, and asource of potential connecting said grid and said first anode.

4. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connecting said first anode to one of theterminals of said first cathode, another impedance element connectingthe other terminal of said first cathode and said pool type cathode,means connecting said grid and said first anode, and means connectingsaid control element and said first cathode.

5. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connecting said first anode and oneterminal of said first cathode, another impedance element connecting theother terminal of said first cathode and said pool type cathode, andmeans connecting said second anode and said control element to saidfirst cathode.

6. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connecting said first anode and oneterminal of said first cathode, another impedance element connecting theother terminal of said cathode and said pool type cathode, meansconnecting said second anode and said control element to said firstcathode, and means connecting said grid with said first anode.

7. In an electron discharge tube system, a cathode having a pair ofterminals for supplying heating current to said cathode, an anode, agrid, an impedance element connecting said anode and one terminal ofsaid cathode, the other terminal of said cathode being connected withthe negative terminal of a. source of current, and said anode beingconnected with the positive terminal of said source for passing currentfrom said source through said impedance element and said cathode inseries.

8. In an electron discharge tube, means forming two chambers, a firstcathode, a grid, and a' first anode in one said chamber; a pool typecathode, a second anode, and a control element in the other saidchamber; an impedance element connected in circuit with at least one ofsaid anodes, and means connecting said grid with said impedance elementto cause biasing of said grid as a result of current fiow through saidimpedance element.

9. In an electron discharge tube, an anode and a positive terminalconnected thereto, a thermionic cathode and a negative terminalconnected thereto, an impedance element connected in series with saidcathode between said terminals, and grid means for controlling electronflow between said cathode and said anode.

ALBERT G. THOMAS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 887,642 Jackson May 12, I9081,976,391 Foster Oct. 9, 1934 2,071,057 Baruch Feb. 16, 1937 2,113,392Baruch Apr. 5, 1938 2,117,246 Haglund May 10, 1938 2,220,077 Cofiin Nov.5, 1940 2,235,504 Rennie Mar. 18, 1941 2,263,171 Hays Nov. 18, 19412,314,691 Dawson Mar. 23, 1943 2,322,754 Undy June 20, 1943 2,369,767Abernathy Feb. 20, 1945

